Largest Batch of Earth-size, Habitable Zone Planets
Our Spitzer Space
Telescope has revealed the first known system of seven Earth-size planets
around a single star. Three of these planets are firmly located in an area
called the habitable zone, where liquid water is most likely to exist on a
by several ground-based telescopes, Spitzer confirmed the existence of two of
these planets and discovered five additional ones, increasing the number of
known planets in the system to seven.
the FIRST time three terrestrial
planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure
both the masses and the radius for habitable zone Earth-sized planets.
these seven planets could have liquid water, key to life as we know it, under
the right atmospheric conditions, but the chances are highest with the three in
the habitable zone.
40 light-years (235 trillion miles) from Earth, the system of planets is
relatively close to us, in the constellation Aquarius. Because they are located
outside of our solar system, these planets are scientifically known as
exoplanets. To clarify, exoplanets are
planets outside our solar system that orbit a sun-like star.
animation, you can see the planets orbiting the star, with the green area
representing the famous habitable zone, defined as the range of distance to the
star for which an Earth-like planet is the most likely to harbor abundant
liquid water on its surface. Planets e, f and g fall in the habitable zone of
Spitzer data, the team precisely measured the sizes of the seven planets and
developed first estimates of the masses of six of them. The mass of the seventh
and farthest exoplanet has not yet been estimated.
comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would
be the size of a golf ball.
their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further
observations will not only help determine whether they are rich in water, but
also possibly reveal whether any could have liquid water on their surfaces.
The sun at
the center of this system is classified as an ultra-cool dwarf and is so cool
that liquid water could survive on planets orbiting very close to it, closer
than is possible on planets in our solar system. All seven of the TRAPPIST-1
planetary orbits are closer to their host star than Mercury is to our sun.
planets also are very close to each other. How close? Well, if a person was
standing on one of the planet’s surface, they could gaze up and potentially see
geological features or clouds of neighboring worlds, which would sometimes
appear larger than the moon in Earth’s sky.
planets may also be tidally-locked to their star, which means the same side of
the planet is always facing the star, therefore each side is either perpetual
day or night. This could mean they have weather patterns totally unlike those
on Earth, such as strong wind blowing from the day side to the night side, and
extreme temperature changes.
TRAPPIST-1 planets are likely to be rocky, and they are very close to one
another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto,
Ganymede – as good comparisons in our solar system. All of these moons are also
tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than
Jupiter, yet much warmer.
How Did the Spitzer Space Telescope Detect this System?
an infrared telescope that trails Earth as it orbits the sun, was well-suited
for studying TRAPPIST-1 because the star glows brightest in infrared light,
whose wavelengths are longer than the eye can see. Spitzer is uniquely
positioned in its orbit to observe enough crossing (aka transits) of the
planets in front of the host star to reveal the complex architecture of the
Every time a planet passes by, or transits, a star, it blocks out some
light. Spitzer measured the dips in light and based on how big the dip, you can
determine the size of the planet. The timing of the transits tells you how long
it takes for the planet to orbit the star.
TRAPPIST-1 system provides one of the best opportunities in the next decade to
study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will
help astronomers plan for follow-up studies using our upcoming James Webb Space
Telescope, launching in 2018. With much greater sensitivity, Webb will be
able to detect the chemical fingerprints of water, methane, oxygen, ozone and
other components of a planet’s atmosphere.
At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like:
The Past, Present and Future of Exploration on Mars
Today, we’re celebrating the Red Planet! Since our first close-up picture of Mars in 1965, spacecraft voyages to the Red Planet have revealed a world strangely familiar, yet different enough to challenge our perceptions of what makes a planet work.
You’d think Mars would be easier to understand. Like Earth, Mars has polar ice caps and clouds in its atmosphere, seasonal weather patterns, volcanoes, canyons and other recognizable features. However, conditions on Mars vary wildly from what we know on our own planet.
Join us as we highlight some of the exploration on Mars from the past, present and future:
Our Viking Project found a place in history when it became the first U.S. mission to land a spacecraft safely on the surface of Mars and return images of the surface. Two identical spacecraft, each consisting of a lander and an orbiter, were built. Each orbiter-lander pair flew together and entered Mars orbit; the landers then separated and descended to the planet’s surface.
Besides taking photographs and collecting other science data, the two landers conducted three biology experiments designed to look for possible signs of life.
In 1997, Pathfinder was the first-ever robotic rover to land on the surface of Mars. It was designed as a technology demonstration of a new way to deliver an instrumented lander to the surface of a planet. Mars Pathfinder used an innovative method of directly entering the Martian atmosphere, assisted by a parachute to slow its descent and a giant system of airbags to cushion the impact.
Pathfinder not only accomplished its goal but also returned an unprecedented amount of data and outlived its primary design life.
Spirit and Opportunity
In January 2004, two robotic geologists named Spirit and Opportunity landed on opposite sides of the Red Planet. With far greater mobility than the 1997 Mars Pathfinder rover, these robotic explorers have trekked for miles across the Martian surface, conducting field geology and making atmospheric observations. Carrying identical, sophisticated sets of science instruments, both rovers have found evidence of ancient Martian environments where intermittently wet and habitable conditions existed.
Both missions exceeded their planned 90-day mission lifetimes by many years. Spirit lasted 20 times longer than its original design until its final communication to Earth on March 22, 2010. Opportunity continues to operate more than a decade after launch.
Mars Reconnaissance Orbiter
Our Mars Reconnaissance Orbiter left Earth in 2005 on a search for evidence that water persisted on the surface of Mars for a long period of time. While other Mars missions have shown that water flowed across the surface in Mars’ history, it remained a mystery whether water was ever around long enough to provide a habitat for life.
In addition to using the rover to study Mars, we’re using data and imagery from this mission to survey possible future human landing sites on the Red Planet.
The Curiosity rover is the largest and most capable rover ever sent to Mars. It launched November 26, 2011 and landed on Mars on Aug. 5, 2012. Curiosity set out to answer the question: Did Mars ever have the right environmental conditions to support small life forms called microbes?
Early in its mission, Curiosity’s scientific tools found chemical and mineral evidence of past habitable environments on Mars. It continues to explore the rock record from a time when Mars could have been home to microbial life.
Space Launch System Rocket
We’re currently building the world’s most powerful rocket, the Space Launch System (SLS). When completed, this rocket will enable astronauts to begin their journey to explore destinations far into the solar system, including Mars.
The Orion spacecraft will sit atop the Space Launch System rocket as it launches humans deeper into space than ever before. Orion will serve as the exploration vehicle that will carry the crew to space, provide emergency abort capability, sustain the crew during the space travel and provide safe re-entry from deep space return velocities.
The Mars 2020 rover mission takes the next step in exploration of the Red Planet by not only seeking signs of habitable conditions in the ancient past, but also searching for signs of past microbial life itself.
The Mars 2020 rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a “cache” on the surface of Mars. The mission will also test a method for producing oxygen from the Martian atmosphere, identify other resources (such as subsurface water), improve landing techniques and characterize weather, dust and other potential environmental conditions that could affect future astronauts living and working on the Red Planet.
For decades, we’ve sent orbiters, landers and rovers, dramatically increasing our knowledge about the Red Planet and paving the way for future human explorers. Mars is the next tangible frontier for human exploration, and it’s an achievable goal. There are challenges to pioneering Mars, but we know they are solvable.
If you dropped a water balloon on a bed of nails, you’d expect it to burst spectacularly. And you’d be right – some of the time. Under the right conditions, though, you’d see what a high-speed camera caught in the animation above: a pancake-shaped bounce with nary a leak. Physically, this is a scaled-up version of what happens to a water droplet when it hits a superhydrophobic surface.
Water repellent superhydrophobic surfaces are covered in microscale roughness, much like a bed of tiny nails. When the balloon (or droplet) hits, it deforms into the gaps between posts. In the case of the water balloon, its rubbery exterior pulls back against that deformation. (For the droplet, the same effect is provided by surface tension.) That tension pulls the deformed parts of the balloon back up, causing the whole balloon to rebound off the nails in a pancake-like shape. For more, check out this video on the student balloon project or the original water droplet research. (Image credits: T. Hecksher et al., Y. Liu et al.; via The New York Times; submitted by Justin B.)
We’re incredibly lucky to live on a planet
drenched in water, nestled in a perfect distance from our sun and wrapped with
magnetic fields keeping our atmosphere intact against harsh radiation and space
We know from recent research that life can
persist in the cruelest of environments here on Earth, which gives us hope to
finding life thriving on other worlds. While we have yet to find life outside
of Earth, we are optimistic about the possibilities, especially on other ocean
worlds right here in our solar system.
So…What’s the News?!
Two of our veteran missions are providing
tantalizing new details about icy, ocean-bearing moons of Jupiter and Saturn,
further enhancing the scientific interest of these and other “ocean worlds” in
our solar system and beyond!
scientists announce that a form of energy for life appears to exist in Saturn’s
moon Enceladus, and Hubble
researchers report additional evidence of plumes erupting from Jupiter’s moon
The Two Missions: Cassini and Hubble
spacecraft has found that hydrothermal vents in the ocean of Saturn’s icy moon Enceladus
are producing hydrogen gas, which could potentially provide a chemical energy
source for life.
Cassini discovered that this little moon of
Saturn was active in 2005. The discovery that Enceladus has jets of gas and icy
particles coming out of its south polar region surprised the world. Later we
determined that plumes of material are coming from a global ocean under the icy
crust, through large cracks known as “tiger stripes.”
We have more evidence now – this time sampled
straight from the plume itself – of hydrothermal activity, and we now know the
water is chemically interacting with the rock beneath the ocean and producing
the kind of chemistry that could be used by microbes IF they happened to be
This is the culmination of 12 years of
investigations by Cassini and a capstone finding for the mission. We now know Enceladus
has nearly all the ingredients needed for life as we know it.
The Cassini spacecraft made its deepest dive
through the plume on Oct. 28, 2015. From previous flybys, Cassini determined
that nearly 98% of the gas in the plume is water and the rest is a mixture of
other molecules, including carbon dioxide, methane and ammonia.
instruments provided evidence of hydrothermal activity in the ocean. What we
really wanted to know was…Is there hydrogen being produced that microbes could
use to make energy? And that’s exactly what we found!
To be clear…we haven’t discovered microbes at
Enceladus, but vents of this type at Earth host these kinds of life. We’re
cautiously excited at the prospect that there might be something like this at
Europa is one of the four major moons of
Jupiter, about the size of our own moon but very different in appearance. It’s
a cold, icy world with a relatively smooth, bright surface crisscrossed with
dark cracks and patches of reddish material.
What makes Europa interesting is that it’s believed
to have a global ocean, underneath a thick crust of ice. In fact, it’s got
about twice as much ocean as planet Earth!
In 2014, we detected evidence of intermittent
water plumes on the surface of Europa, which is interesting because they may
provide us with easier access to subsurface liquid water without having to
drill through miles of ice.
And now, in 2016, we’ve found one particular
plume candidate that appears to be at the same location that it
was seen in 2014.
This is exciting because if we can establish that a
particular feature does repeat, then it is much more likely to be real and we
can attempt to study and understand the processes that cause it to turn on or
This plume also happens to coincide with an
area where Europa is unusually warm as compared to the surrounding terrain. The
plume candidates are about 30 to 60 miles (50 to 100 kilometers) in height and are well-positioned for
observation, being in a relatively equatorial and well-determined location.
What Does All This Mean and What’s Next?
Hubble and Cassini are inherently different
missions, but their complementary scientific discoveries, along with the synergy
between our current and planned missions, will help us in finding out whether
we are alone in the universe.
Hubble will continue to observe Europa. If
you’re wondering how we might be able to get more information on the Europa
plume, the upcoming Europa Clipper mission
will be carrying
a suite of 9 instruments to investigate whether the mysterious icy moon could harbor conditions favorable for life. Europa Clipper is slated to launch in the 2020s.
This future mission will be able to study the
surface of Europa in great detail and assess the habitability of this moon.
Whether there’s life there or not is a question for this future mission to
back to the Ice Age more than 60,000 years ago, the forest of cypress
trees once breathed carbon dioxide above the water’s surface.
Long ago, sea levels were about 400 feet lower than they are now,
and the forest is increasingly relevant to researchers considering that
our planet is being inundated with sea level rise caused by climate
The forest is “considered a treasure trove of information” when it
comes to understanding Earth’s ancient history, according to a Reddit AMA. “Scientific analysis of the site is ongoing.” Read more (7/19/17)
In their newest video, the Slow Mo Guys recreated one of my favorite effects: vibration-driven droplet ejection. For this, they use a Chinese spouting bowl, which has handles that the player rubs after partially filling the bowl with water. By rubbing, a user excites a vibrational mode in the bowl. Watch the GIFs above and you can actually see the bowl deforming steadily back and forth. This is the fundamental mode, and it’s the same kind of vibration you’d get from, say, ringing a bell.
Without a high-speed camera, the bowl’s vibration is pretty hard to see, but it’s readily apparent from the water’s behavior in the bowl. In the video, Gav and Dan comment that the ripples (actually Faraday waves) on the water always start from the same four spots. That’s a direct result of the bowl’s movement; we see the waves starting from the points where the bowl is moving the most, the antinodes. In theory, at least, you could see different generation points if you manage to excite one of the bowl’s higher harmonics. The best part, of course, is that, once the vibration has reached a high enough
amplitude, the droplets spontaneously start jumping from the water surface! (Video and image credits: The Slow Mo Guys; submitted by effyeah-artandfilm)